It has been demonstrated that lysine and histidine residues in glutamine synthetase and glucose-6-phosphate dehydrogenase are among several amino acid residues that are oxidized to carbonyl derivatives by mixed-function oxidation systems. The Fenton reagent comprised of Fe-chelate and hydrogen peroxide was shown to catalyze the conversion of all common amino acids to ammonia and their corresponding Alpha-keto acid derivatives. A number of physiological chelating agents (citrate, nucleoside di- and tri- phosphates, orthophosphate, pyrophosphate) as well as nonphysiological chelating agents (EDTA, EGTA, DETAPAC, o-phenanthroline, and Alpha-dipyridyl) stimulate the oxidative deamination reaction about 2-4-fold. In addition to chelated iron, it was found that unchelated iron and also bicarbonate ion are essential for deamination to occur.